Juvenile diabetes or type 1 diabetes (T1D) is an autoimmune disorder that affects almost 3 million Americans. T1D is caused by autoimmune driven destruction of insulin producing beta-cells. It is a costly and chronic disease that requires daily insulin injections. Currently there is no cure and patients will eventually develop a series of complications associated with disease. The mechanisms of beta-cell destruction by autoreactive lymphocytes are pooriy understood. Therefore, understanding the process of pathogenic lymphocyte migration into the islets and consequent beta-cell destruction is of paramount importance and will lead to the identification of new therapeutic targets. The goal of the proposed study is to utilize novel retrogenic and transcriptome analysis technologies to identify target molecules specific to diabetogenic T cells responsible for beta-cell damage. We will use a unique retroviral TCR transgenic system developed in our laboratory in order to rapidly generate mice with multiple TCR specificities for various islet antigens. In this study we will compare three TCRs with vastly different diabetogenic potential including a hyper-diabetogenic TCR, BDC10.1, which causes extremely rapid diabetes with 100% penetrance. In Aim 1, I will assess two main areas of T cell function related to increased diabetes: tissue infiltration and effector function. The kinetics of islet entry will be compared based on the time and degree of insulitis. Insulitis will be visually assessed by immunohistochemical analysis, and the number of CD4+ T cells infiltrating the islets will be quantified by flow cytometry. T cells from the islets and pancreatic lymph nodes of retrogenic mice will be compared based on T cell cytolytic function and pro-inflammatory cytokine secretion using flow cytometric analysis. In Aim 2, we will identify the effector mechanism of diabetogenic T cells through the use of custom designed low density microarray (LDA) and the highly innovative lllumina transcriptome sequencing platform. We will utilize these approaches to identify a "genetic signature" of highly diabetogenic T cells with the goal of uncovering novel genes important for the development of T cell driven diabetes in NOD mice. Lay Language: Juvenile diabetes is induced when certain cells of the immune system attack and destroy insulin-producing cells in the pancreas. A number of different cells is found in the pancreas during diabetes; however, which ones are responsible for most of the damage and the molecules that they secrete is not completely understood. In this study we plan to identify the molecules that are produced by the most dangerous cells with the eventual goal of finding drugs that will selectively inhibit these molecules.